History of non-paroxysmal form of AF as defined by the HRS/EHRA/ECAS Consensus Statement:-Persistent AF shall be defined as continuous AF that is sustained beyond seven days. Episodes of AF in which a decision is made to electrically or pharmacologically cardiovert the patient after greater than or equal to 48 hours of AF but prior to 7 days, should also be classified as persistent AF episodes.-Longstanding persistent AF shall be defined as continuous AF of greater than 12 months duration. The performance of a successful cardioversion (sinus rhythm >30 seconds) within 12 months of an ablation procedure with documented early recurrence of AF with 30 days should not alter the classification of AF as longstanding persistent.

Subject is scheduled to undergo elective open cardiac surgical procedure(s) to be performed on cardiopulmonary bypass for one or more of the following: Coronary Artery Bypass Grafting, Mitral valve repair or replacement, Aortic valve repair or replacement, Tricuspid valve repair or replacement. In conjunction with these procedure patent foramen ovale (PFO) or atrial septal defect (ASD) repair are allowed.

The patient (or their legally authorized representative) agrees to participate in this study by singing the IRB approved informed consent form.

Willing and able to return for scheduled follow up visits.

Key Exclusion Criteria

Stand along AF without indication(s) for concomitant cardiac surgery.

Need for emergent cardiac surgery (i.e., cardiogenic shock).

Preoperative need for an intra-aortic balloon pump or intravenous inotropes.

Pregnancy or desire to get pregnant for the duration of the study concomitant surgical procedure through the thirty six (36) month follow up period).

Enrolled in another clinical trial that could confound the results of this study.